Risner is known for his 1572 publication of "Opticae thesaurus: Alhazeni Arabis libri septem, nuncprimum editi; Eiusdem liber De Crepusculis et nubium ascensionibus, Item Vitellonis Thuringopoloni libri X", an edition of works by Ibn al-Haitham and Erazmus Ciolek Witelo, two men who were both early pioneers in the field of optics. The publication became a major benefit to a number of mathematicians and scientists, such as Kepler, Huygens, and Descartes.

He was the first to propose the idea of a portable camera obscura, which purportedly was to be used to help create artistic topographical drawings. His idea consisted of a lightweight wooden hut that had small holes fitted with lenses in each wall, and a cube of paper placed in the centre for drawing.

English translation of the inscription above is: "In year 1580 at 15th of September, died in Christ at the age of 47, the well famous Friedrich Risner, an outstanding, excellent mathematician, who passed to soil here, will expect the sound of trumpet."